99m Tc-radiolabeled GE11-modified peptide for ovarian tumor targeting.

Background: Ovarian cancer is a serious threat for women health and the early diagnosis of this cancer might improves the survival rate of patients. The use of the targeted radiopharmaceuticals could be a non-invasive and logical method for tumor imaging. The aim of this study was to radiolabel GE11 peptide as a new specific probe for imaging of ovarian tumor.
Methods: HYNIC-SSS-GE11 peptide was labeled with ^99m Tc using tricine as a coligand. The ^99m Tc-tricine-HYNIC-SSS-GE11 peptide was evaluated for specific cellular binding in three cell lines with different levels of EGFR expression. Tumor targeting was assessed in SKOV3 tumor bearing mice.
Results: By using tricine as a coligand, labeling yield was more than 98% and the stability of the radiolabelled peptide in human serum up to 4 h was 96%. The in vitro cell uptake test showed that this radiolabeled peptide had a good affinity to SKOV3 cells with dissociation constant of 73 nM. The in vivo results showed a tumor/muscle ratio of 3.2 at 4 h following injection of ^99m Tc-tricine-HYNIC-SSS-GE11 peptide.
Conclusions: Results of this study showed that ^99m Tc-tricine-HYNIC-SSS-GE11 peptide could be a promising tool for diagnosis and staging of ovarian cancer. ^99m Tc-tricine-HYNIC-SSS-GE11, a novl targeted agent for ovarian tumor imaging.